deadweight

Your Claude Code setup charges rent. Some of it never shows up for work.

Every skill, subagent and MCP server you install gets loaded into context at the start of every single session — whether you use it or not. You pay for it in tokens, every time, forever.

Nothing tells you which ones you actually use.

$ deadweight

deadweight 62 sessions · /home/user/my-repo

DEAD WEIGHT loaded every session, never called
  mcp server jira                  11,412 chars  (~2,853 tok)   never used
  mcp server Artlist                2,072 chars  (~518 tok)     never used
  skill      dataviz                1,447 chars  (~361 tok)     never used
  agent      data-migrator          1,097 chars  (~274 tok)     never used
  skill      legacy-deploy            340 chars  (~85 tok)      never used
  … and 12 more
  tools      197 of 201 never called 5,998 chars  (~1,499 tok)  names only; schemas load on demand

  22,410 chars (~5,602 tokens) per session for nothing — 61% of the 36,500 you load

HOOKS wall-clock you pay on every run
  Stop          ~/.claude/stop-hook-git-check.sh   1,842 runs   4m 21s  avg 142ms
  PostToolUse   ~/.claude/format.sh                  611 runs   1m 02s  avg 101ms

Then you delete what you never use, and get that context back.

There is nothing to install to find out:

git clone https://github.com/hjalti-hub/deadweight && cd deadweight
python3 -m deadweight

Zero dependencies. Nothing leaves your machine.

How it knows

Claude Code already writes down everything you need. Every session is logged to ~/.claude/projects/*/*.jsonl, and those files record two things nobody reads together:

What got loaded. Each session's transcript stores the actual text of the skill listing, the subagent listing, the MCP instruction blocks and the tool roster. So the cost of each item is measured, not estimated — deadweight counts the characters Claude Code actually put in your context.

What got used. Every tool_use block names the tool that ran. Skills name themselves when invoked, subagents name themselves when spawned, and MCP tools carry their server in the name (mcp__jira__create_issue).

Join those two and you get the only question that matters: what am I paying for that has never once done anything?

Privacy

This reads your session history, so it's worth being precise about what it touches.

It never reads message text. Not your prompts, not Claude's replies, not tool inputs, not file contents. The parser skips them entirely — it collects names, counts, character totals and durations, and nothing else. There's a test that asserts exactly this: parse a transcript containing secrets, then assert none of them survive anywhere in the result.

Nothing leaves your machine. No network calls, no telemetry, no API key. It's a local file reader.

Install

A clone is enough — run it as a module from inside the checkout:

git clone https://github.com/hjalti-hub/deadweight && cd deadweight
python3 -m deadweight

To run it from any directory, install it from that clone:

pip install .        # or: pipx install .

Requires Python 3.9+.

On PyPI it is claude-deadweight. PyPI does not allow the bare name deadweight, so pip install claude-deadweight is what installs it. The command you type is still deadweight, and the import is still deadweight.

Use

Once installed you can drop the python3 -m prefix; from a clone, keep it.

deadweight                     # weigh every session on this machine
deadweight --project my-repo   # only sessions from a matching directory
deadweight --since 30          # only the last 30 days
deadweight --used              # also show what is earning its keep
deadweight --all               # every row, not just the top ones
deadweight --json              # machine-readable

--project accepts either separator, so my-repo and my/repo both work — the on-disk encoding can't tell them apart.

What it measures

That last row is worth calling out. Hook cost is otherwise completely invisible: nothing fails, everything just gets slower, gradually. These are the durations Claude Code itself recorded.

Honest limits

• "Never used" is only as good as your history. In 3 sessions it means nothing; in 200 it means a lot. The report tells you which situation you're in and warns you below 5 sessions.
• It measures what the transcript records. MCP instruction blocks are measured exactly. An MCP server's tool schemas may cost more on top of that, and are not separately itemised.
• Deferred tools are already cheap. Claude Code lists them by name and loads schemas on demand, so 200 tools cost a few thousand characters, not hundreds of thousands. Don't go deleting tools expecting a windfall.
• Something rarely used may still be worth keeping. This tells you the price; whether it's worth paying is your call. Sort by cost_per_call in the JSON if you want the borderline cases.
• Project names are lossy. Claude Code encodes the working directory with dashes, so a real dash and a path separator look identical. Project labels are for grouping, not for opening.

Library use

from deadweight.transcripts import load
from deadweight.analyze import build

report = build(load(since_days=90))
for item in report.dead:
    print(item.kind, item.name, item.chars, "chars/session, never called")

Related

whyskill answers the other half of the same question. It reads your configuration and proves a skill can't fire — truncated descriptions, name collisions, shadowing. This one reads your history and shows what doesn't fire, and what that costs you.

Static proof, and empirical evidence.

Contributing

The transcript format isn't a published API, so the most useful contribution is a failing test with a real (redacted) transcript shape that this parser gets wrong.

python3 -m unittest discover -s tests -t .

License

MIT